// Copyright 2016 The Draco Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Functions for creating prediction schemes for decoders using the provided
// prediction method id.

#ifndef DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_PREDICTION_SCHEME_DECODER_FACTORY_H_
#define DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_PREDICTION_SCHEME_DECODER_FACTORY_H_

#include "draco/draco_features.h"

#include "draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_constrained_multi_parallelogram_decoder.h"
#include "draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_geometric_normal_decoder.h"
#include "draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_multi_parallelogram_decoder.h"
#include "draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_parallelogram_decoder.h"
#include "draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_tex_coords_decoder.h"
#include "draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_tex_coords_portable_decoder.h"
#include "draco/compression/attributes/prediction_schemes/prediction_scheme_decoder.h"
#include "draco/compression/attributes/prediction_schemes/prediction_scheme_delta_decoder.h"
#include "draco/compression/attributes/prediction_schemes/prediction_scheme_factory.h"
#include "draco/compression/mesh/mesh_decoder.h"

namespace draco {

// Factory class for creating mesh prediction schemes. The factory implements
// operator() that is used to create an appropriate mesh prediction scheme in
// CreateMeshPredictionScheme() function in prediction_scheme_factory.h
template <typename DataTypeT>
struct MeshPredictionSchemeDecoderFactory {
    // Operator () specialized for the wrap transform. Wrap transform can be used
    // for all mesh prediction schemes. The specialization is done in compile time
    // to prevent instantiations of unneeded combinations of prediction schemes +
    // prediction transforms.
    template <class TransformT, class MeshDataT,
              PredictionSchemeTransformType Method>
    struct DispatchFunctor {
        std::unique_ptr<PredictionSchemeDecoder<DataTypeT, TransformT>> operator()(
                    PredictionSchemeMethod method, const PointAttribute *attribute,
                    const TransformT &transform, const MeshDataT &mesh_data,
        uint16_t bitstream_version) {
            if (method == MESH_PREDICTION_PARALLELOGRAM) {
                return std::unique_ptr<PredictionSchemeDecoder<DataTypeT, TransformT>>(
                           new MeshPredictionSchemeParallelogramDecoder<DataTypeT, TransformT,
                           MeshDataT>(
                               attribute, transform, mesh_data));
            }
#ifdef DRACO_BACKWARDS_COMPATIBILITY_SUPPORTED
            else if (method == MESH_PREDICTION_MULTI_PARALLELOGRAM) {
                return std::unique_ptr<PredictionSchemeDecoder<DataTypeT, TransformT>>(
                           new MeshPredictionSchemeMultiParallelogramDecoder<
                           DataTypeT, TransformT, MeshDataT>(attribute, transform,
                                   mesh_data));
            }
#endif
            else if (method == MESH_PREDICTION_CONSTRAINED_MULTI_PARALLELOGRAM) {
                return std::unique_ptr<PredictionSchemeDecoder<DataTypeT, TransformT>>(
                           new MeshPredictionSchemeConstrainedMultiParallelogramDecoder<
                           DataTypeT, TransformT, MeshDataT>(attribute, transform,
                                   mesh_data));
            }
#ifdef DRACO_BACKWARDS_COMPATIBILITY_SUPPORTED
            else if (method == MESH_PREDICTION_TEX_COORDS_DEPRECATED) {
                return std::unique_ptr<PredictionSchemeDecoder<DataTypeT, TransformT>>(
                           new MeshPredictionSchemeTexCoordsDecoder<DataTypeT, TransformT,
                           MeshDataT>(
                               attribute, transform, mesh_data, bitstream_version));
            }
#endif
            else if (method == MESH_PREDICTION_TEX_COORDS_PORTABLE) {
                return std::unique_ptr<PredictionSchemeDecoder<DataTypeT, TransformT>>(
                           new MeshPredictionSchemeTexCoordsPortableDecoder<
                           DataTypeT, TransformT, MeshDataT>(attribute, transform,
                                   mesh_data));
            } else if (method == MESH_PREDICTION_GEOMETRIC_NORMAL) {
                return std::unique_ptr<PredictionSchemeDecoder<DataTypeT, TransformT>>(
                           new MeshPredictionSchemeGeometricNormalDecoder<
                           DataTypeT, TransformT, MeshDataT>(attribute, transform,
                                   mesh_data));
            }
            return nullptr;
        }
    };

    // Operator () specialized for normal octahedron transforms. These transforms
    // are currently used only by the geometric normal prediction scheme (the
    // transform is also used by delta coding, but delta predictor is not
    // constructed in this function).
    template <class TransformT, class MeshDataT>
    struct DispatchFunctor<TransformT, MeshDataT,
               PREDICTION_TRANSFORM_NORMAL_OCTAHEDRON_CANONICALIZED> {
        std::unique_ptr<PredictionSchemeDecoder<DataTypeT, TransformT>> operator()(
                    PredictionSchemeMethod method, const PointAttribute *attribute,
                    const TransformT &transform, const MeshDataT &mesh_data,
        uint16_t bitstream_version) {
            if (method == MESH_PREDICTION_GEOMETRIC_NORMAL) {
                return std::unique_ptr<PredictionSchemeDecoder<DataTypeT, TransformT>>(
                           new MeshPredictionSchemeGeometricNormalDecoder<
                           DataTypeT, TransformT, MeshDataT>(attribute, transform,
                                   mesh_data));
            }
            return nullptr;
        }
    };
    template <class TransformT, class MeshDataT>
    struct DispatchFunctor<TransformT, MeshDataT,
               PREDICTION_TRANSFORM_NORMAL_OCTAHEDRON> {
        std::unique_ptr<PredictionSchemeDecoder<DataTypeT, TransformT>> operator()(
                    PredictionSchemeMethod method, const PointAttribute *attribute,
                    const TransformT &transform, const MeshDataT &mesh_data,
        uint16_t bitstream_version) {
            if (method == MESH_PREDICTION_GEOMETRIC_NORMAL) {
                return std::unique_ptr<PredictionSchemeDecoder<DataTypeT, TransformT>>(
                           new MeshPredictionSchemeGeometricNormalDecoder<
                           DataTypeT, TransformT, MeshDataT>(attribute, transform,
                                   mesh_data));
            }
            return nullptr;
        }
    };

    template <class TransformT, class MeshDataT>
    std::unique_ptr<PredictionSchemeDecoder<DataTypeT, TransformT>> operator()(
                PredictionSchemeMethod method, const PointAttribute *attribute,
                const TransformT &transform, const MeshDataT &mesh_data,
    uint16_t bitstream_version) {
        return DispatchFunctor<TransformT, MeshDataT, TransformT::GetType()>()(
                   method, attribute, transform, mesh_data, bitstream_version);
    }
};

// Creates a prediction scheme for a given decoder and given prediction method.
// The prediction schemes are automatically initialized with decoder specific
// data if needed.
template <typename DataTypeT, class TransformT>
std::unique_ptr<PredictionSchemeDecoder<DataTypeT, TransformT>>
        CreatePredictionSchemeForDecoder(PredictionSchemeMethod method, int att_id,
                const PointCloudDecoder *decoder,
const TransformT &transform) {
    if (method == PREDICTION_NONE)
        return nullptr;
    const PointAttribute *const att = decoder->point_cloud()->attribute(att_id);
    if (decoder->GetGeometryType() == TRIANGULAR_MESH) {
        // Cast the decoder to mesh decoder. This is not necessarily safe if there
        // is some other decoder decides to use TRIANGULAR_MESH as the return type,
        // but unfortunately there is not nice work around for this without using
        // RTTI (double dispatch and similar concepts will not work because of the
        // template nature of the prediction schemes).
        const MeshDecoder *const mesh_decoder =
            static_cast<const MeshDecoder *>(decoder);

        auto ret = CreateMeshPredictionScheme<
                   MeshDecoder, PredictionSchemeDecoder<DataTypeT, TransformT>,
                   MeshPredictionSchemeDecoderFactory<DataTypeT>>(
                       mesh_decoder, method, att_id, transform, decoder->bitstream_version());
        if (ret)
            return ret;
        // Otherwise try to create another prediction scheme.
    }
    // Create delta decoder.
    return std::unique_ptr<PredictionSchemeDecoder<DataTypeT, TransformT>>(
               new PredictionSchemeDeltaDecoder<DataTypeT, TransformT>(att, transform));
}

// Create a prediction scheme using a default transform constructor.
template <typename DataTypeT, class TransformT>
std::unique_ptr<PredictionSchemeDecoder<DataTypeT, TransformT>>
        CreatePredictionSchemeForDecoder(PredictionSchemeMethod method, int att_id,
const PointCloudDecoder *decoder) {
    return CreatePredictionSchemeForDecoder<DataTypeT, TransformT>(
               method, att_id, decoder, TransformT());
}

}  // namespace draco

#endif  // DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_PREDICTION_SCHEME_DECODER_FACTORY_H_
